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From: Dmitry Osipenko <digetx@gmail.com>
To: Ulf Hansson <ulf.hansson@linaro.org>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	linux-pm@vger.kernel.org
Cc: Jonathan Hunter <jonathanh@nvidia.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Rajendra Nayak <rnayak@codeaurora.org>,
	Stephan Gerhold <stephan@gerhold.net>,
	Roja Rani Yarubandi <rojay@codeaurora.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Stephen Boyd <sboyd@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 3/4] PM: domains: Drop/restore performance state votes for devices at runtime PM
Date: Thu, 3 Jun 2021 22:02:59 +0300	[thread overview]
Message-ID: <a7f55fce-dd4a-22ab-f7e2-4821e765a634@gmail.com> (raw)
In-Reply-To: <20210603093438.138705-4-ulf.hansson@linaro.org>

03.06.2021 12:34, Ulf Hansson пишет:
> A subsystem/driver that need to manage OPPs for its device, should
> typically drop its vote for the OPP when the device becomes runtime
> suspended. In this way, the corresponding aggregation of the performance
> state votes that is managed in genpd for the attached PM domain, may find
> that the aggregated vote can be decreased. Hence, it may allow genpd to set
> the lower performance state for the PM domain, thus avoiding to waste
> energy.
> 
> To accomplish this, typically a subsystem/driver would need to call
> dev_pm_opp_set_rate|opp() for its device from its ->runtime_suspend()
> callback, to drop the vote for the OPP. Accordingly, it needs another call
> to dev_pm_opp_set_rate|opp() to restore the vote for the OPP from its
> ->runtime_resume() callback.
> 
> To avoid boilerplate code in subsystems/driver to deal with these things,
> let's instead manage this internally in genpd.
> 
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
> 
> Changes in v2:
> 	- Rebased.
> 	- A few minor cosmetic changes.
> 	- Deal with the error path in genpd_runtime_resume().

I tested this on NVIDIA Tegra by removing the boilerplate code from
drivers' RPM and haven't noticed any problems, the performance state is
dropped/restored as expected. Thank you.

  parent reply	other threads:[~2021-06-03 19:03 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-03  9:34 [PATCH v2 0/4] PM: domains: Avoid boilerplate code for DVFS in subsystem/drivers Ulf Hansson
2021-06-03  9:34 ` [PATCH v2 1/4] PM: domains: Split code in dev_pm_genpd_set_performance_state() Ulf Hansson
2021-06-03  9:34 ` [PATCH v2 2/4] PM: domains: Return early if perf state is already set for the device Ulf Hansson
2021-06-03  9:34 ` [PATCH v2 3/4] PM: domains: Drop/restore performance state votes for devices at runtime PM Ulf Hansson
2021-06-03  9:55   ` Viresh Kumar
2021-06-03 10:31     ` Ulf Hansson
2021-06-03 11:17       ` Ulf Hansson
2021-06-04  3:53         ` Viresh Kumar
2021-06-04  7:45           ` Ulf Hansson
2021-06-07  4:47             ` Viresh Kumar
2021-06-09 12:25               ` Ulf Hansson
2021-06-03 19:02   ` Dmitry Osipenko [this message]
2021-06-03 19:08     ` Dmitry Osipenko
2021-06-04  7:20       ` Ulf Hansson
2021-06-03  9:34 ` [PATCH v2 4/4] PM: domains: Drop/restore performance state votes for devices at system PM Ulf Hansson
2021-06-03 10:20   ` Ulf Hansson
2021-06-03 11:15     ` Mark Brown
2021-06-03 13:48       ` Ulf Hansson
2021-06-08 12:53     ` Stephan Gerhold
2021-06-08 14:08       ` Ulf Hansson
2021-06-08 14:20         ` Mark Brown
2021-06-08 14:39           ` Ulf Hansson
2021-06-08 15:37         ` Stephan Gerhold
2021-06-03 11:12 ` [PATCH v2 0/4] PM: domains: Avoid boilerplate code for DVFS in subsystem/drivers Stephan Gerhold
2021-06-03 15:27   ` Ulf Hansson
2021-06-03 17:14     ` Stephan Gerhold
2021-06-04  7:18       ` Ulf Hansson
2021-06-04  8:23         ` Stephan Gerhold
2021-06-04 10:57           ` Ulf Hansson
2021-06-04 11:50             ` Stephan Gerhold
2021-06-11 16:42               ` Rafael J. Wysocki

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